Method to determine hold over ballistic information

ABSTRACT

A handheld rangefinder device operable to determine ballistic hold over information is disclosed. The rangefinder device generally includes a range sensor operable to determine a first range to a target, a tilt sensor operable to determine an angle to the target relative to the device, and a computing element, coupled with the range sensor and the tilt sensor, operable to determine a hold over value based on the first range and the determined angle. Such a configuration facilitates accurate firearm and bow use by providing ranges and hold over values without requiring time-consuming and manual user calculations.

RELATED APPLICATION

The present application is a continuation patent application and claimspriority benefit, with regard to all common subject matter, ofearlier-filed U.S. patent application titled “HANDHELD RANGEFINDEROPERABLE TO DETERMINE HOLD OVER BALLISTIC INFORMATION”, Ser. No.11/314,593, filed Dec. 21, 2005. The identified earlier-filedapplication is hereby incorporated by reference into the presentapplication.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to handheld rangefinders that assist auser in compensating for deviations in projectile trajectory. Moreparticularly, the present invention relates to a handheld rangefinderthat utilizes a range sensor and a tilt sensor to determine hold overballistic information corresponding to projectile trajectories.

2. Description of the Related Art

Hunters and other firearm and bow users commonly utilize handheldrangefinders to determine ranges to targets. Generally, handheldrangefinders utilize lasers to acquire ranges for display to a hunter.Utilizing the displayed ranges, the hunter makes sighting corrections tofacilitate accurate shooting. Unfortunately, due to variations inelevation and slope, the ranges determined by handheld rangefindersoften are not accurate representations of the horizontal distancesprojectiles must travel.

For example, as shown in FIG. 1, a hunter positioned above or below atarget may be provided a range, 9 yards for instance, that is differentthan the actual horizontal distance to the target, 5 yards for instance,thereby resulting in inaccurate shooting. Further, handheld rangefindersfail to determine hold over ballistic information corresponding to theamount by which hunters must vary their aim, thereby forcing hunters tomanually perform hold over calculations.

Devices operable to compensate for slope and elevation utilizing lasersand inclinometers have been developed to alleviate some of theseproblems. For example, U.S. patent application Ser. Nos. 10/867,429 and10/964,206, which are incorporated herein by reference, disclosetelescope sights and other optical devices having a laser range sensorand an inclinometer. Unfortunately, these devices have a limited fieldof vision, must be attached to a firearm or bow, or are unable toprovide hold over ballistic information. Thus, hunters are unable toavail themselves of the beneficial aspects of handheld rangefinders,such as increased field of vision, maneuverability, and portability,while correcting for range, slope, elevation, and rangefinderorientation utilizing hold over ballistic information.

SUMMARY OF THE INVENTION

The present invention solves the above-described problems and provides adistinct advance in the art of handheld rangefinders. More particularly,the invention provides a handheld rangefinder that utilizes a rangesensor and a tilt sensor to determine hold over ballistic informationcorresponding to projectile trajectories. Such a configurationfacilitates accurate firearm and bow use by providing ranges and holdvalues without requiring time-consuming and manual user calculations.

In one embodiment, the present invention provides a rangefinder devicefor determining hold over ballistic information. The device generallyincludes a range sensor operable to determine a first range to a target,a tilt sensor operable to determine an angle to the target relative tothe device, and a computing element, coupled with the range sensor andthe tilt sensor, operable to determine a hold over value based on thefirst range and the determined angle.

In another embodiment, the rangefinder device includes a laser rangesensor operable to determine a first range to a target, a tilt sensoroperable to determine an angle to the target relative to the device, amemory comprising a database of ranges and corresponding projectile dropvalues, a computing element operable to determine a hold over valuebased on the first range and the determined angle by acquiring one ofthe projectile drop values from the database and modifying the acquiredprojectile drop value utilizing the determined angle, and a displayoperable to indicate the first range and the hold over value.

In another embodiment, the rangefinder device includes a laser rangesensor operable to determine a first range to a target, a tilt sensorincluding an inclinometer operable to determine an angle to the targetrelative to the device, an input operable to receive configurationinformation from a user, a memory comprising a database of ranges andcorresponding projectile drop values, a computing element operable todetermine a hold over value based on the first range, the configurationinformation, and the determined angle by acquiring one of the projectiledrop values from the database and modifying the acquired projectile dropvalue utilizing the determined angle, a display operable to indicate thefirst range and the hold over value, and a portable handheld housing.

In another embodiment, the present invention provides a method fordetermining hold-over ballistic information. The method generallycomprises determining a first range to a target, determining an angle tothe target, and determining a hold over value based on the first rangeand the determined angle by acquiring a projectile drop value andmodifying the projectile drop value utilizing the determined angle.

Other aspects and advantages of the present invention will be apparentfrom the following detailed description of the preferred embodiments andthe accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is described in detailbelow with reference to the attached drawing figures, wherein:

FIG. 1 is a schematic view showing various distances between a hunterand a target;

FIG. 2 is a block diagram of a rangefinder device configured inaccordance with various preferred embodiments of the present invention;

FIG. 3 is a rear perspective view of the rangefinder device of FIG. 2;

FIG. 4 is a front perspective view of the rangefinder device of FIGS.2-3;

FIG. 5 is a diagram illustrating a first range to a target and anassociated projectile trajectory;

FIG. 6 is a diagram illustrating a second range and an associatedprojectile trajectory to the target of FIG. 4 when the target iselevated;

FIG. 7 is a diagram illustrating an angle to an elevated target relativeto the device;

FIG. 8 is a diagram illustrating various angles and projectiletrajectories relative to the device;

FIG. 9 is a chart illustrating a plurality of ballistic curves; and

FIG. 10 a schematic view of a target observed while looking through thedevice, a display indicating the first range, the second range, and ahold over value.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following detailed description of the invention references theaccompanying drawings that illustrate specific embodiments in which theinvention can be practiced. The embodiments are intended to describeaspects of the invention in sufficient detail to enable those skilled inthe art to practice the invention. Other embodiments can be utilized andchanges can be made without departing from the scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

Turning now to the drawing figures, and particularly FIGS. 1-10, arangefinder device 10 is shown constructed in accordance with variouspreferred embodiments of the present invention. The device 10 generallyincludes a range sensor 12 for determining a first range to a target T,a tilt sensor 14 for determining an angle to the target T, a computingelement 16 coupled with the range sensor 12 and the tilt sensor 14 fordetermining ballistic information relating to the target T based on thefirst range and the determined angle, a memory 18 for storing data suchas ballistic information and a computer program to control thefunctionality of the device 10, and a portable handheld housing 20 forhousing the range sensor 12, the tilt sensor 14, the computing element16, the memory 18, and other components described below.

A computer program preferably controls input and operation of the device10. The computer program includes at least one code segment stored in oron a computer-readable medium residing on or accessible by the device 10for instructing the range sensor 12, tilt sensor 14, computing element16, and any other related components to operate in the manner describedherein. The computer program is preferably stored within the memory 18and comprises an ordered listing of executable instructions forimplementing logical functions in the device 10. However, the computerprogram may comprise programs and methods for implementing functions inthe device 10 which are not an ordered listing, such as hard-wiredelectronic components, programmable logic such as field-programmablegate arrays (FPGAs), application specific integrated circuits,conventional methods for controlling the operation of electrical orother computing devices, etc.

Similarly, the computer program may be embodied in any computer-readablemedium for use by or in connection with an instruction execution system,apparatus, or device, such as a computer-based system,processor-containing system, or other system that can fetch theinstructions from the instruction execution system, apparatus, ordevice, and execute the instructions. The computer-readable medium mayeven be paper or another suitable medium upon which the program isprinted, as the program can be electronically captured, via forinstance, optical scanning of the paper or other medium, then compiled,interpreted, or otherwise processed in a suitable manner, if necessary,and then stored in a computer memory.

The device 10 and computer program described herein are merely examplesof a device and a program that may be used to implement the presentinvention and may be replaced with other devices and programs withoutdeparting from the scope of the present invention.

Referring to FIGS. 2-4, the range sensor 12 is operable to determine thefirst range to the target T from the device 10. The range sensor 12 maybe any conventional sensor or device for determining range. The firstrange preferably represents a length of an imaginary line drawn betweenthe device 10 and the target T, as shown in FIG. 5, such as the numberof feet, meters, yards, miles, etc, directly between the device 10 andthe target T. Thus, the first range may correspond to a line of sight(LOS) between the device 10 and the target T.

Preferably, the range sensor 12 is a laser range sensor which determinesthe first range to the target by directing a laser beam at the target T,detecting a reflection of the laser beam, measuring the time requiredfor the laser beam to reach the target and return to the range sensor12, and calculating the first range of the target T from the rangesensor 12 based on the measured time. Thus, the range sensor 12 mayinclude an emitter and a detector to emit the laser beam and then detectthe reflection of the laser beam in a generally conventional manner.

The range sensor 12 is operable to determine a range to a target evenwhen objects, such as trees, people, vehicles, foliage, etc, arepositioned between the device and the target. As a result, the rangesensor 12 may determine the first range to the target T in a variety ofsituations, including in outdoor situations where various trees and/orother foliage may obstruct a direct view of the target T.

The range sensor 12 may also include memory and processing capabilitiesseparate from the computing element 16 and memory 18, such that therange sensor is operable to determine the range to the target T withoutthe assistance of additional components. However, the range sensor 12may rely upon the capabilities provided by the computing element 16 andmemory 18 to specifically calculate and determine the first range.

The range sensor 12 may alternatively or additionally include otherrange sensing components, such as conventional optical, radio, sonar, orvisual range sensing devices to determine the first range in asubstantially conventional manner.

The tilt sensor 14 is operable to determine the angle to the target Tfrom the device 10 relative to the horizontal. Thus, as shown in FIGS.5, 7, and 8, if the device 10 and the target T are both positioned on aflat surface having no slope, the angle would be zero. As shown in FIGS.6 and 8, if the device 10 is positioned below the target T the slopebetween the device 10 and the target T is positive, the angle would bepositive. Conversely, as shown in FIG. 8, if the device 10 is positionedabove the target T, such that the slope between the device 10 and thetarget T is negative, the angle would be negative.

It will be appreciated that the angle is not dependent upon the specificcontours of the ground, surface, or surfaces between the device 10 andthe target T, but rather the angle is preferably determined based on theorientation of the device 10, as described below.

The tilt sensor 14 preferably determines the angle by sensing theorientation of the device 10 relative to the target T and thehorizontal. The orientation of the device 10 changes based on therelative position of the target T to the device 10, as a user of thedevice 10 aligns the device 10 with the target T and views the target Tthrough an eyepiece 22 and an opposed lens 24, as described in moredetail below. Thus, the orientation of the device 10, specifically thetilt of the device 10 along its longitudinal axis relative to thehorizontal, indicates if the target T is above or below the device 10.

For example, if the target T is above the device 10, the user of thedevice 10 would tilt the device 10 such that a distal end 26 of thedevice 10 would be raised relative to a proximate end 28 of the device10 and the horizontal. Similarly, if the target T is below the device10, the user of the device 10 would tilt the device 10 such that thedistal end 26 of the device 10 would be lowered relative to theproximate end 28 of the device and the horizontal. T

The tilt sensor 14 preferably determines the angle of the target to thedevice 10 based on the amount of tilt, that is the amount the proximateend 28 is raised or lowered relative to the distal end 26, as describedbelow. The tilt sensor 14 may determine the tilt of the device, and thusthe angle, through various orientation determining elements. Forinstance, the tilt sensor 14 may utilize one or more single-axis ormultiple-axis magnetic tilt sensors to detect the strength of a magneticfield around the device 10 or tilt sensor 14 and then determine the tiltof the device 10 and the angle accordingly. The tilt sensor 14 maydetermine the tilt of the device using other or additional conventionalorientation determine elements, including mechanical, chemical,gyroscopic, and/or electronic elements, such as a resistivepotentiometer.

Preferably, the tilt sensor 14 is an electronic inclinometer, such as aclinometer, operable to determine both the incline and decline of thedevice 10 such that the angle may be determined based on the amount ofincline or decline. Thus, as the device 10 is aligned with the target Tby the user, and the device 10 is tilted such that its proximate end 28is higher or lower than its distal end 26, the tilt sensor 14 willdetect the amount of tilt which is indicative of the angle.

The computing element 16 is coupled with the range sensor 12 and thetilt sensor 14 to determine ballistic information relating to the targetT, including hold over ballistic information, as is discussed in moredetail below. The computing element 16 may be a microprocessor,microcontroller, or other electrical element or combination of elements,such as a single integrated circuit housed in a single package, multipleintegrated circuits housed in single or multiple packages, or any othercombination. Similarly, the computing element 16 may be any elementwhich is operable to determine hold over ballistic information from thefirst range and angle as described below. Thus, the computing element 16is not limited to conventional microprocessor or microcontrollerelements and may include any element which is operable to perform thefunctions described below.

The memory 18 is coupled with the computing element 16 and is operableto store the computer program and a database including ranges,projectile drop values, and configuration information, as is discussedin detail below. The memory 18 may be, for example, an electronic,magnetic, optical, electro-magnetic, infrared, or semi-conductor system,apparatus, device, or propagation medium. More specific, although notinclusive, examples of the memory 18 include the following: volatile andnon-volatile memory, an electrical connection having one or more wires,a portable computer diskette, a random access memory (RAM), a read-onlymemory (ROM), an erasable, programmable, read-only memory (EPROM orFlash memory), an optical fiber, a portable compact disc (CD), or adigital video disc (DVD). However, the memory 18 may be of any formoperable to store the necessary computer program and data.

The memory 18 may be integral with the computing element 16, such thatthe memory 18 and the computing element 16 are stored within or on thesame wafer, die, or package, or the memory 18 may be discrete with thecomputing element 16 such that the memory 18 and the computing element16 are stored on different wafers, dies, or packages. Additionally, thememory 18 may be coupled with other components, such as the range sensor12 and tilt sensor 14, to enable the other components to utilize thefunctionality provided by the memory 18. The memory 18 may also beaccessible by other external devices, such as conventional computingdevices, to enable data stored within the memory, such as the databaseor the computer program, to be easily accessed or modified byconventional computing devices.

The device 10 also preferably includes a display 30 to indicate relevantinformation such as the target T, the first range, the angle, andballistic information such as hold over information, a reticle or otheralignment element, etc. The display 30 may be a conventional electronicdisplay, such as a LED, TFT, or LCD display. Preferably, the display 30is viewed by looking through the eyepiece 22 such that the user mayalign the target T and simultaneously view relevant information, asshown in FIG. 10.

For instance, the user may look through the eyepiece 22, align thetarget T, view the target T, and generally simultaneously view thedisplay 30 to determine the first range, the angle θ, hold over value,and/or other relevant information. The generally simultaneous viewing ofthe target T and the relevant information enables the user to quicklyand easily determine ranges and ballistic information corresponding tovarious targets by moving the device 10 in an appropriate direction anddynamically viewing the change in the relevant information on thedisplay 30.

The portable handheld housing 20 houses the range sensor 12, tilt sensor14, computing element 16, and/or other desired elements such as thedisplay 30, one or more inputs 32, eyepiece 22, lens 24, laser emitter,laser detector, etc. The handheld housing 20 enables the device 10 beeasily and safely transported and maneuvered for convenient use in avariety of locations.

For example, the portable handheld housing 20 may be easily transportedin a backpack for use in the field. Additionally, the location of thecomponents on or within the housing 20, such as the position of theeyepiece 22 on the proximate end 28 of the device 10, the position ofthe lens 24 on the distal end 26 of the device, and the location of theinputs 32, enables the device 10 to be easily and quickly operated bythe user with one hand without a great expenditure of time or effort.

The inputs 32 are coupled with the computing element 16 to enable users,third parties, or other devices to share information with the device 10.The inputs 32 is generally associated with the housing 20, such as byphysical connection through wires, etc, or wirelessly utilizingconventional wireless protocols. Thus, the inputs 32 need not bephysically coupled with the housing 20. However, the inputs 32 arepreferably positioned on the housing 20 to enable the user tosimultaneously view the display 30 through the eyepiece 22 and functionthe inputs 32.

The inputs 32 preferably comprise one or more functionable inputs suchas buttons, switches, scroll wheels, etc, a touch screen associated withthe display 30, voice recognition elements, pointing devices such asmice, touchpads, trackballs, styluses, combinations thereof, etc.Further, the inputs 32 may comprise wired or wireless data transferelements such as removable memory including the memory 18, networkconnections, data transceivers, etc, to enable the user and otherdevices or parties to remotely interface with the device 10.

In operation, the user aligns the device 10 with the target T and viewsthe target T on the display 30. The device 10 may provide generallyconventional optical functionality, such as magnification or otheroptical modification, by utilizing the lens 24 and/or the computingelement 16. Preferably, the device 10 provides an increased field ofvision as compared to conventional riflescopes to facilitateconventional rangefinding functionality.

Further, the user may function the inputs 32 to control the operation ofthe device 10. For example, the user may activate the device 10, provideconfiguration information as discussed below, and/or determine a firstrange, a second range, angle, and ballistic information by functioningone or more of the inputs 32.

For instance, the user may align the target T by centering the reticleover the target T and functioning at least one of the inputs 32 to causethe range sensor 12 to determine the first range. Alternatively, therange sensor 12 may dynamically determine the first range for allaligned objects such that the user is not required to function theinputs 32 to determine the first range. Similarly, the tilt sensor 14may dynamically determine the angle for all aligned objects or the tiltsensor may determine the angle when the user functions at least one ofthe inputs 32. Thus, the ranges, angle, and ballistic informationdiscussed below may be dynamically displayed to the user.

In various embodiments, the device 10 enables the user to provideconfiguration information to facilitate determination of ballisticinformation, including hold over information, by the computing element16. The configuration information includes mode information to enablethe user to select between various projectile modes, such as bowhuntingand firearm modes discussed below in more detail, to enable the device10 to provide information corresponding to the selected mode, as isdescribed below. Further, the configuration information may includeprojectile information, such as a bullet size, caliber, grain, shape,type, etc and firearm caliber, size, type, sight-in distance, etc.

Preferably, the provided configuration information corresponds to one ofa plurality of ballistic curves. For example, the user may select onecurve, or provide an indication relating to one curve, instead ofentering detailed and complex ballistic information such as bulletshape, grain, caliber, etc. As shown in FIG. 9, five sample curves,C1-C5, are provided each corresponding to a particular ballisticprofile. For instance, C4 may correspond to a pistol profile, C3 maycorrespond to a small-caliber rifle profile, C2 may correspond to arifle profile, C5 may correspond to a medium-power rifle profile, C1 maycorrespond to a high-power rifle profile, etc. As should be appreciated,innumerable combinations of ballistic curves may exist eachcorresponding to any ballistic profile. Various ballistic curves andassociated projectile drops are disclosed in U.S. Pat. No. 3,990,155,which is incorporated herein by reference.

The user may provide the configuration information to the device 10 byfunctioning the inputs 32. For example, the user may depress one or moreof the inputs 32 to provide configuration information and/or the usermay provide electronic data utilizing the inputs 32 through a dataconnection, etc. Additionally, the display 30 may present prompts,indication elements, menus, selectable lists, etc, to help the user inproviding the configuration information.

Further, the memory 18 may include information corresponding toconfiguration information to enable the user-provided configurationinformation to be stored by the memory 18. Also, the memory 18 mayinclude a database of configuration information, such as the pluralityof ballistic curves or data corresponding to the ballistic curves, toenable the user to select configuration information from the data storedby the memory 18. For example, the display 30 may provide a listing ofstored configuration information for selection by the user.

In embodiments where the memory 18 comprises non-volatile memory, theconfiguration information may be permanently stored by the user suchthat the user need not repeatedly provide the information each time thedevice 10 is used. However, due to the ease in which one of theplurality of ballistic curves may be selected, utilization ofnon-volatile memory is not necessary in all embodiments.

In various embodiments, the device 10 is operable to determine a secondrange to the target T and display an indication of the second range tothe user. The computing element 16 is coupled with the range sensor 12and the tilt sensor 14 to determine the second range to the target Tbased on the first range and the determined angle. The second range maybe determined statically such that the second range is determined onlyat desired intervals or upon input by the user. Conversely, the secondrange may be dynamically determined such that the second range may becontinuously updated as new first ranges or angles or provided. Thus,the second range may be accurately determined for moving targets, suchas a hunted animal, as the change in the targets position is accountedfor by the dynamic calculations.

The computing element 16 determines the second range to the target T byadjusting the first range based upon the angle. Preferably, thecomputing element 16 determines the second range by multiplying thefirst range by the sine or cosine of the angle. For instance, when thehunter is positioned above the target, the first range is multiplied bythe sine of the angle to determine the second range. When the hunter ispositioned below the target, the first range is multiplied by the cosineof the angle to determine the second range.

Thus, the second range preferably represents a horizontal distance theprojectile must travel such that the estimated trajectory of theprojectile generally intersects with the target T. In contrast, thefirst range represents the length of an imaginary line, such as a lineof sight, between the device 10 and the target T, which is asubstantially straight line, as described above. As is known in the art,projectiles which are not self-propelled, such as bullets, golf balls,footballs, arrows, etc, move through air according to a generallyparabolic (ballistic) curve due primarily to the effects of gravity andair drag. In situations where the angle is zero, the parabolic movementof the projectile does not substantially affect the range calculation,such that the first range and the second range may be substantiallyequal.

As shown in FIG. 6, in situations where the angle is non-zero, such aswhen the target T is positioned above or below the device 10, theparabolic movement of the projectile affects the range calculation, suchthat the projectile may have to travel a longer or shorter distance toreach the target T. Thus, the second range provides an accuraterepresentation to the user of the flat-ground distance the projectilemust travel to intersect the target T.

For example, referring to FIG. 1, the device 10 would determine thefirst range to be 9 yards, as the first range generally corresponds to aline of sight between the device 10 and the target T. The device 10would determine the second range, utilizing the angle acquired by thetilt sensor 14, to be 5 yards, representing the horizontal distance theprojectile must travel to strike the target T.

Although the second range may be dynamically presented by the display 30without requiring user input, the second range is preferably displayedonly when the device 10 is in bowhunting mode as indicated by theuser-provided information. Such a configuration may be desirable as atrue horizontal distance to a target, as indicated by the second range,may be of little use to firearms that have compact ballistic curves dueto the high velocity at which fired projectiles travel. In contrast,bow-fired projectiles are fired with controllable force by the user atgenerally short ranges such that the second range greatly facilitatestargeting, as is shown in FIG. 1.

The device 10 is further operable to determine ballistic informationincluding a hold over value corresponding to an amount of hold over. Asis known in the art, hold over refers to the amount by which the usermust aim high, or above the target, to compensate for the effects oftrajectory, projectile drop, and angle. Thus, the hold over valuedetermined by the device 10 provides an indication of how much, or towhat degree, the user must aim high in relation to the target toaccurately fire a projectile.

FIG. 8 illustrates three exemplary projectile trajectories andcorresponding bullet drops. For each angle, positive, zero, andnegative, three paths are illustrated: path 1 corresponds to a line ofdeparture, which represents an a projectile trajectory comprising ahypothetical infinite straight line; path 2 corresponds to a parabolic(ballistic) trajectory resulting from the effects of gravity and drag onpath 1; and path 3 corresponds to a light of sight to the target. As canbe seen, the difference between path 1 and path 2 corresponds toprojectile drop, which varies as the range and angle changes.

As is known in the art and as shown in FIG. 8, firing a projectile atuphill or downhill angles affects the trajectory of the projectile bycausing the projectile to impact high relative to the projectile pathfor level fire. The deviations in trajectory grow larger as range andangle increase. Further, projectiles impact slightly higher when fireddownhill than uphill at the same angle due to the varying effects ofgravity on uphill and downhill trajectories. Thus, to correct forprojectile drop, it is generally necessary to aim above a target.

Additionally, as will be appreciated by those skilled in the art, theamount of hold over is dependent on the range at which a firearm issighted in. For instance, firearms are typically sighted in at 100yards, to build-in appropriate hold over for projectile drop, such thata user need not hold over when firing at targets at 100 yards, but wouldneed to hold over for targets substantially over 100 yards. The device10 preferably utilizes a default sight in distance of 100 yards, whichmay be stored in the memory 18. However, the device 10 may utilize auser-provided sight in distance, as discussed above, to determine thehold over value.

The device 10 may determine the hold over value utilizing variousmethods. Preferably, the computing element 16 determines the hold overvalue utilizing the first range and the determined angle by acquiring aprojectile drop value corresponding to the first range and modifying theprojectile drop value utilizing the determined angle. The projectiledrop value corresponds to the amount of vertical projectile drop at aparticular range and at zero angle. Similarly, the computing element 16may acquire a plurality of projectile drop values and modify theplurality of projectile drop values utilizing the acquired angle todetermine hold over values accordingly.

The computing element 16 may acquire the projectile drop value from thememory 18. For instance, as described above, the memory 18 may include adatabase of ballistic information, including a listing, table, chart,etc, of projectile drop values corresponding to various ranges andconfiguration information. For instance, the database may include datacorresponding to the chart of FIG. 9 to enable the retrieval of aprojectile drop value, in minutes of angle (MOA), inches, yards,centimeters, reticle positions, etc, based upon the first range.

Preferably, the projectile drop value is retrieved utilizing both thefirst range and the configuration information. For instance, as is shownin FIG. 9, the projectile drop value may be dependent upon theparticular projectile or firearm utilized, such that retrieving aprojectile drop value corresponding to a utilized projectile facilitatesaccurate shooting. Thus, in embodiments where the user selects one ofthe plurality of ballistic curves, the projectile drop value ispreferably retrieved utilizing the selected ballistic curve and thefirst range.

The computing element 16 may also or additionally acquire the projectiledrop value utilizing a look-up table or other database element. Forexample, the database may include an ordered listing, table, and/orrelational listing of ranges, configuration information, and projectiledrop values, such that the projectile drop value may be acquired byproviding the range and configuration information, such as projectilecurve, type, size, etc. Such data corresponding to projectile dropvalues, ranges, and other ballistic information is commonly availablethrough numerous sources such as bullet manufacturers, firearmmanufacturers, internet databases, textbooks, etc, and may be storedwithin the memory 18 for retrieval by the computing element 16 and/or tohelp the user in providing configuration information.

Further, as will be appreciated by those skilled in the art, theprojectile drop value may be dependent on the range at which the firearmor bow is sighted in. For instance, the chart of FIG. 9 indicates aprojectile drop value of zero at 100 yards as a firearm sighted-in at100 yards and thus on a level surface would experience no additionaldrop for which compensation is required by the user.

The computing element 16 may utilize a default sight-in range of 100yards and retrieve projectile drop values accordingly and/or thecomputing element 16 may utilizing a user-provided sight-in range andretrieve projectile drop values accordingly or modify a retrievedprojectile drop value utilizing conventional algorithms to reflectvariations in sight-in range.

To compensate for angled projectile trajectories in determining the holdover value, the computing element 16 is operable to utilize the angledetermined by the tilt sensor 14 to modify the acquired projectile dropvalue. As explained above and shown in FIG. 8, the projectile drop valuevaries according to angle. The amount of variance may be expressutilizing a cosine of the acquired angle.

Specifically, the hold over value may be determined by the computingelement 16 by multiplying the projectile drop value corresponding to thefirst range by the cosine of the acquired angle. The hold over value,configuration information, projectile drop values, and other data may beprovided and/or displayed utilizing various units. For example, the holdover value and projectile drop values may correspond to minutes ofangle, inches, centimeters, reticle positions, combinations thereof,etc. As shown in FIG. 10, the hold over value may be displayed by thedisplay 30 as both a numerical value in inches, 24 inches for example,or as one or more reticles, such as a first reticle and a secondreticle.

For instance, the first reticle may be a fixed reticle that correspondsto the sight-in range while the second reticle may be adynamically-displayed reticle that reflects changes to the first reticlebased upon the determined hold over value. The hold over value may alsorefer to one or more reticles on the user's riflescope, such as thenumber of dots on the a reticle that the user must aim high.

Further, the information presented on the display 30 may be dependentupon the first range to the target T. Specifically, in situations wherethe first range is less than 100 yards, the first and second ranges maybe displayed, but not the hold over value or angle, as the second range,representing true horizontal distance, is often more important forshort-range accuracy than hold over information. For instance, when thedevice 10 is in bowhunting mode the display 30 presents the first andsecond ranges but not the hold over value.

In contrast, where the second range is greater than 100 yards, the firstrange, the hold over value, and/or the angle may be displayed, but notthe second range, as the hold over value is often more important forlong-range accuracy than true horizontal distance. For instance, whenthe device 10 is in firearms mode, the first range and the hold overvalue are preferably shown but not the second range.

Thus, the provided bowhunting mode is preferably limited to ranges lessthan 100 yards and does not present an indication of the hold over valuewhile the provided firearms mode is not limited to any particular rangesand presents an indication of the first range and the hold over value.As should be appreciated by those skilled in the art, the firearms modemay additionally be operable to calculate a hold under value utilizingthe first range and the determined angle.

Although the invention has been described with reference to thepreferred embodiments illustrated in the attached drawings, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims.

Having thus described the preferred embodiment of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

1. A method for determining hold over ballistic information, the methodcomprising the steps of: determining a first range to a target;determining an angle to the target; and determining a hold over valuebased on the first range and the determined angle by acquiring aprojectile drop value and modifying the projectile drop value utilizingthe determined angle.
 2. The method as set forth in claim 1, wherein thehold over value is determined by multiplying the acquired projectiledrop value by the cosine of the acquired angle.
 3. The method as setforth in claim 1, further including determining a second range to thetarget by multiplying the first range by the cosine of the acquiredangle.
 4. The method as set forth in claim 1, further includingacquiring configuration information and determining the hold over valuebased upon the first range, the determined angle, and the configurationinformation.
 5. The method as set forth in claim 4, wherein theconfiguration information includes one of a plurality of ballisticcurves.
 6. The method as set forth in claim 5, wherein each ballisticcurve corresponds to a ballistic curves of a projectile.
 7. The methodas set forth in claim 5, wherein each ballistic curve corresponds to aballistic curves of a firearm.
 8. The method as set forth in claim 4,wherein the configuration information includes a sight-in range.
 9. Amethod for determining hold over ballistic information, the methodcomprising the steps of: acquiring configuration information;determining a first range to a target; determining an angle to thetarget; and determining a hold overvalue based on the first range, thedetermined angle and configuration information by acquiring a first dropvalue and modifying the first drop value utilizing the determined angleand a second drop value wherein the configuration informationcorresponds to one of a plurality of ballistic curves and a sight-inrange.
 10. The method as set forth in claim 9, wherein the hold overvalue is determined by multiplying the acquired projectile drop value bythe cosine of the acquired angle.
 11. The method as set forth in claim9, further including determining a second range to the target bymultiplying the first range by the cosine of the acquired angle.
 13. Themethod as set forth in claim 9, wherein each ballistic curve correspondsto a ballistic curves of a projectile.
 14. The method as set forth inclaim 9, wherein each ballistic curve corresponds to a ballistic curvesof a firearm.
 15. The method as set forth in claim 9, wherein the seconddrop value corresponds to the drop value of the ballistic curve at thesight-in range.